Stone tools show ancient settlement high in Andes

The air was thin, the nights were cold, the sun could easily burn the skin. But about 12,000 years ago, small groups of hunter-gatherers found a home very high up in the Peruvian Andes.

Now, their stone tools and other artifacts have revealed their presence at about 14,700 feet above sea level, about as high as the Matterhorn and much higher than Machu Picchu. They lived there nearly 1,000 years earlier than any other known human habitation anywhere above even 13,000 feet, research...